Process of treating steel ingots and the like.



srarns Parana orrrion.

BENJA IN TALBOT, OEIMID'DLESBOROIUGH, ENGLAND.

. PRooEss or TREATING STEEL moors AND THE LrKE.

Specification of Letters Patent. I

Patented May 12, 1908.

Application filed June 15, 1907.. Serial No. 379,150.

' process of treating steel ingots, blooms, slabs,

and like masses before they are rolled down intorails or other finishedproduct, and-it'has for its object providing the'steel mass with asurface or skin-higher in carbon than is obtained when it is solidifiedor cooled in the usual Way, whereby after rolling a harder wearingsurface is obtained.

My invention is more particularly applicable to the manufacture ofrails, as at the present time higher carbons than formerly are beingasked for from the manufacturers of rail steel, andwhen the wholemass'of the material forming the rail is as high in-carbon .as from .75to 1.00 per cent. the rail is apt to ,become treacherous ,under hardconditions "of wear, or if small fractures .are made, or

underlvery low temperatures, whereas if only the surface is hardenedequallygood'wear-ing qualities inthe rail are obtained.

f My invention may be carried out as follows, in the case ofan ingotfor-eXample:' As soon as the steel ingot is stripped from the ingot,mold it; is carried toan inclosed receptacle preferably lined withbrickwork,

which may be previously heated or. not, or

the receptacle may be of metal, such as cast iron. This rece coal,or'other suitable form of carbon, or carbonaceous material, orca'rbon ina gaseous state, which may be previously heated if desired. The carbonshould be pressed in somewhat tightly between the ingot and the outerwall. Some form of mechanical ramming may conveniently be used, but careshould be taken that the pressure is equally gjaplied all round'theexterior of the ingot.

enicompltely filled the ingot is allowed into a rail or other section inthe table may be for example some 8 to 10 inc es larger than the ingotto to remai'nlthils covered for a length of time 'dependenton the amountof carbon to be It is in fact possible to partially melt the car:

bonized metal on the surface if care be not taken to prevent this. Underthese conditions when the ingot is placed in contact with thecarbonaceous covering, while-its interior is liquid or semi-liquid,great heat is given out to the cooler surface of the ingot and it isthis which permits the carbon to be more rapidly absorbed into thesurfac e of the ingot, than if the center of the ingotwas in solidcondition. v v It will be found that the carbon will have penetratedinto the surface of the steel ingot, and one may thus obtain forinstance about .75 to 1.00 per cent. of carbon on the surface whileinterior portions of the ingothas'only about 0.50 to .75 per -centforwhatever percentage the steel may have been cast at. The carbonizedingot is then rolled, or'forged, or preferably heated before beingrolled down ordinary manner, the finished article presenting a hardenedattenuated skin or surface. f

It is a known fact that segregation of carbon and impurities alwaystakesplace toward the center of an ingot or mass and the greatest amountgenerally occurs in the center or about say 25 percent; from the top. Inthe present instance the slower cooling of the ingot will tend todecrease this effect and to.

of the composition improve the uniformity of the mass.

It is sometimes desirable that only part'of the outer surface of theingot or mass should betreated in this way, so that when rolled down,the harder part may form the wearing head of the rail, or article, thepart forming say the web and flange inthe case of a rail remaining ofthe same hardness as the mass of the steel. To accomplish this, when thehot ingot is put into'the receptacle suitable division pieces may beinserted so that the carbon may be brought into contact with any wishedfor part of the ingot or mass and does not'surround it on all sides asit would if such the division pieces were absent.

Where the carbon entirely surrounds ingot or mass a complete unbrokenhardened skin or surface will be obtained in the finished article.

' carbonized by beating them in connection tact while the interior ofthe metalls still desired amount of said the metal, which consists withcoke powder or other suitable form ofcarbon,-buti-n the case of latentand initial.

my invention the heat is employed,

.What I claim is :1

1. The process of treating steel, for the --production of an articlehaving. an exterior portions harder than the body of in casting themolten metal, then placing a surface or surfaces of the mass and ahardening material in conportion or heated. to or above plasticity, andutilizing the latent, heat for effecting the exterior conditionrequisite for the absorption of the 2 The process of treating steel, forthe production of an article having a surface harder than thebody of themetal, whioh'c'onsists in casting the metal and then; placing-the sur- 1face to be hard ened and a hardening mate-.

rial in contact whlle the interior temperature of said-metal 1ssuflicient to produce a Sennliquidcondition in the interior metalr I 3.The process of treating steel, for the vprohardening material,

duction of a shape having a part harder than the remainder, whichconsists in casting the metal,. then bringing ing agent and the part 0dened, utilizingthe latent in efiecting the metal to be harheatofthemetal the desired absorption of saidtogether a hardenhardening agent,,and then shaping said metal. p

4. The process of treating steel, to efiect surface 'carburization' ofand reduce segregation of carbon in the body, inclosing the cast metalin contact with carbon while only,the' interior of,the' mass is fluid,bafllingthe escape of the heat to effect interior heat for securing thesurface 'heat necessary for effecting absorption of carbon by thesurface of "the body. Intestimony whereof l have hereunto set my hand inthe presence of two subscribing Witnesses.

v BENJAMIN TALBOT.

Witnesses: v

; (Er. S. MARSHALL,

.EDWD. T. FOSTER.

which consists 1n 4o slow cooling of the interior and utilizing the

